1. Field of the Invention
The present invention relates to an encrypting algorithm, and in particular to a data encrypting method which is capable of preventing an unauthorized user""s access and wiretap by privately encrypting a certain data at the side of a data transmission using an encrypting algorithm based on an IEEE 1394 serial bus network for thereby providing a service for only an authorized system.
2. Description of the Background Art
Generally, an encryption is directed to converting a data used for a data transmission and receiving operation into a certain format which is not recognizable by an unauthorized user using a certain encryption method or by performing a certain conversion. The encryption is formed of an original data, a key for encrypting the data, and a key for decoding the encrypted data into an original data. In addition, as the above-described encryption method, there are provided a symmetrical encryption method implemented by a key for encoding a data and another key for decoding the encrypted data, and an asymmetrical encryption method which uses a public key.
In an encryption method based on a www security protocol on the network, there are provided a DES(Data Encryption Standard) in which the key of 56 bit length is divided into a 64-bit block and is processed more than 18 times and then is encrypted based on a 1-key encryption method, and a RSA encryption method which is implemented by a 2-key encryption method having different codes each used for encrypting a data and decoding the encrypted data. The RSA encryption method is directed to a 2-key encryption method having different codes each used for encrypting a data and decoding the encrypted data. When encrypting a security data, two xe2x80x9cpublic keysxe2x80x9d which are published as being receiver""s are used for a data receiver, and when decoding the encrypted data, one xe2x80x9cpersonal keyxe2x80x9d which is known merely to data receiver is used for decoding the encrypted data.
An encrypted data is transmitted to an opposite system using the above-described encryption method, and at the opposite side, the encrypted data is decoded or reproduced into an original data using a certain process or an encryption key.
The above-described operation will be explained in detail with reference to FIG. 1.
FIG. 1 is a view illustrating an embodiment for performing a service connection using an encryption. At the side of a transmission, a certain message is encrypted into a cryptogram by an encryption key and is stored. The cryptogram is transmitted to a certain destination system. Thereafter, the cryptogram is decoded into an original message by a certain decoding process. Namely, the thusly transmitted cryptogram is decoded into an original message by a certain decoding process at the side of the destination system, for example, using a decoding key for decoding the cryptogram. At this time, if the destination system solely has a decoding key, a receiver may receive a certain message without informing the contents of a transmission to another receiver who does not have a decoding key based on the encrypted state of the transmitter.
The processes that a certain message is encrypted and the message received at the side of the receiver is decoded, is performed in a state that a message process format is determined based on a certain standard and condition. Therefore, in the case that an unauthorized user accesses the system, an error message or an access impossible message is outputted, so that the unauthorized person can not access the system.
The IEEE 1394 standard is directed to an international standard implemented based on a high speed serial bus apparatus capable of providing an isochronous(real time) and asynchronous transmission. The digital apparatuses are connected by a high speed serial bus based on the IEEE 1394 serial bus network interface card(module). In addition, in the IEEE 1394, a communication node, a computer and home appliance are connected with a single network in a transmission technique between the digital nodes, so that it is possible to implement a multimedia data transmission and receiving operation at a high speed from 100 Mbps to 1 Gbps.
In addition, an IEEE 1394 cable is used for a data interface based on a high bandwidth and is thinner compared to other cables. When a peripheral node connected by the IEEE 1394 cable is in an active state, a multimedia operation characteristic capable of adding or removing a new digital node is possible.
As described above, the IEEE 1394 standard has a high transmission speed and bidirectional communication characteristic. Namely, the IEEE 1394 standard is capable of processing a data at three transmission speeds of 98.304 Mbps, 196.608 Mbps and 393.216 Mbps in accordance with a transmission mode. Therefore, it is possible to effectively transmit a digital audio signal or a motion picture information. A connection with a multimedia peripheral node such as a scanner, a digital camera, a digital video camera, etc. may be possible. since the above-described three transmission speeds are available for other transmission speeds, the 393.216 Mbps transmission mode support both 98.304 Mbps and 196.608 Mbps. In addition, since a bidirectional communication function is excellent, the peripheral system(hereinafter called as a node) having the IEEE 1394 serial bus network interface card(module) is available for a data transmission and receiving operation in a multimedia application field for a video conference using a computer.
FIG. 2 is a view illustrating a state that a plurality of nodes are connected based on a known IEEE 1394 serial bus network. As shown therein, there is provided an IEEE 1394 serial bus network interface card(module)(not shown) for each node for transmitting a data outputted from a certain node to another node for thereby recording or displaying the same. Namely, there are provided an audio system 200, a digital TV 202, a set-top box 204, a computer 206, a printer 208, a scanner 210, and a digital video disk ROM(DVD-ROM) 212 which are interconnected by a bus connection technique of a point-to-point method.
In the above-described structure, if a certain node is disconnected from the IEEE 1394 cable or another node is connected to the same, an IEEE 1394 bus reset operation is performed and initialized. In the initial step, an existing information which is being processed between nodes connected by the IEEE 1394 cable is initialized. Each node is provided with a physical address. Thereafter, the IEEE 1394 interface becomes a standby state for a normal operation.
The IEEE 1394 interface is directed to a method for transmitting data and supports an isochronous(real time) and asynchronous transmission.
In the asynchronous transmission mode, a data and a hierarchical information are transmitted using an address, and in the asynchronous transmission mode, when transmitting data, a channel number is transmitted without using the address. For example, the isochronous transmission mode is used for transmitting a multimedia information which has a time-based limit like a motion picture or audio data, and the asynchronous transmission mode is used for transmitting an information used for a certain apparatus which is not operated in real time such as a printer 108 or a scanner 110. In addition, each node receives a protocol supported by the node when transmitting a certain data. For example, an AV/C protocol is adapted to the audio system 100, the digital TV 102, etc., and the CD-ROM/DVD-ROM 112 is capable of transmitting a data based on a SBP-2(Serial Bus Protocol-2). In addition, the protocol adapted to the printer 108 is used for transmitting a certain data based on the DP protocol. These protocols are separated from each other by a 1-bit flag and are stored in a protocol packet data provided to each node.
In the data transmission at each node in the isochronous and asynchronous transmission modes based on a connection with the IEEE 1394 cable, a protocol identification packet data is transmitted to the network and is formed to another node, so that the data is transmitted and received with respect to the node having the same protocol.
In the above-described conventional IEEE 1394 serial bus network, there is not a function for providing a detail access method with respect to itself information which is changed at each time when a certain data is transmitted from the transmission side to a receiving side.
Accordingly, it is an object of the present invention to provide a data encryption method which is capable of transmitting an encryption algorithm and encryption data to a corresponding node when a service is requested from a certain node with respect to a certain system by setting an encryption algorithm in the system and decoding an encrypted data transmitted from the system in accordance with an encryption algorithm and displaying the same, so that a certain user can use a service.
To achieve the above objects, there is provided a data encryption method on an IEEE 1394 serial bus network, which includes the steps of requesting a private encryption at a data transmission side node using a previously set encryption algorithm at a certain node, recognizing and checking whether the data transmission side node set an encryption at a certain node, transmitting an encrypted data at the data transmission side node when a certain node requests a service at the data transmission side node, and decoding the encrypted data using a decoding key at a certain node for a normal use of the data.
In the above-described method, the encryption setting operation may be performed by a bit padding method.
In addition, in the above-described method, the node of the data transmission side may request a password input based on an encryption algorithm, and when a password is not properly inputted, a service invalid message is displayed on a certain node.
In the above-described method, in a state that an encryption is set at the data transmission side node by a certain node, when setting an encryption at the data transmission side node by another node, an encryption deny message may be displayed on another node.
Additional advantages, objects and features of the invention will become more apparent from the description which follows.